Variation of DNA amount in 22 populations of Tanacetum L. (Asteraceae, Anthemideae) in Iran: Palynology, Morphology and Ecological implications

Seed of 22 populations of Tanacetum (12 species and 7 subspecies) and seed of Pisum sativum, Petunia hybrid and Triticum aestivum as internal standards were selected and were caltivated under the same greenhouse conditions. Genome size (C-value, mass of DNA per haploid nucleus) was estimated by flow cytometry. Data from the study were analyzed by SPSS 16 software. The result revealed genome size is positively correlated with pollen morphometric, shape and colour of capitule, type of inflorecences and corology of species, but is negatively correlated with size of seed and environmental factors such as altitude and humidity of the habitat. The variation in the 2C value (mass of DNA per diploid nucleus) was high, with a range from 3.84 pg in Tanacetum parthenium (Tehran) to 24.12 pg in Tanacetum polycephalum subsp. farsicum. As wellas a 6.28-fold variation in 2C value and 2.73 fold variation in C value were found. Key words: Altitude , Genome size, Pollen grains, Morphology, Flow cytometry.